1. Field of the Invention
The present invention relates to a thermosensitive recording label, and more particularly to a liner-less thermosensitive recording label having a thermosensitive adhesive layer.
2. Discussion of the Related Art
A thermosensitive recording material is known which has a substrate, a thermosensitive coloring layer formed on the substrate, and when necessary, a protective layer formed on the thermosensitive coloring layer. Such a thermosensitive recording material is now widely used as a recording material for price labels which are attached on packages of goods or on the goods themselves. The thermosensitive price labels are usually produced as follows:
(1) a pressure sensitive adhesive layer is formed on one side of the substrate of the thermosensitive recording material which has a thermosensitive coloring layer on the opposite side of the substrate and optionally a protective layer formed thereon; PA0 (2) a liner is superimposed on the pressure sensitive adhesive layer to prevent the pressure sensitive adhesive layer from adhering to the thermosensitive coloring layer or the protective layer when the recording material is wound; PA0 (3) the recording material with the liner is slit to a desired width; and PA0 (4) the slit recording material with the liner is then dyed to form a series of labels on the liner after symbols or characters are printed thereon, when necessary. PA0 (1) the liner has larger dimensions than the thermosensitive recording material and has to be attached to the thermosensitive recording material not only during storage but also during an image recording process, resulting in handling difficulty; PA0 (2) when attaching an image recorded label to a good, the label must be removed from the liner, resulting in low operation efficiency and productivity; PA0 (3) the liner must be disposed of after being removed from the image recorded label, resulting in environmental pollution; and PA0 (4) manufacturing cost is relatively high because the liner is expensive and many processes are required for making the thermosensitive recording label with a liner. In attempting to solve these problems, liner-less thermosensitive recording materials have been proposed. For example, a liner-less thermosensitive recording material having a microencapsulated adhesive layer, or having a releasing layer on a protective layer which can easily release from a pressure-sensitive adhesive layer even when the liner-less thermosensitive recording material is wound, has been disclosed in Japanese Laid-Open Utility Model Publications Nos. 59-43972 and 59-46265 and Japanese Laid-Open Patent Publication No. 60-54842. However, these labels have a drawback in that the adhesive layer has too weak adhesive strength to securely adhere to various goods, or symbols or characters cannot be printed on the releasing layer because of the high releasability of the releasing layer. For these reasons, these liner-less thermosensitive recording labels are not in practical use. PA0 (1) the thermosensitive adhesive layer tends to adhere to the thermosensitive coloring layer when the recording material is wound, resulting in occurrence of the so-called blocking problem; and PA0 (2) the adhesive strength is inadequate to securely adhere the label to films such as polyvinyl chloride films, polyethylene films and the like which are used for wrapping foods. PA0 3,3-bis(p-dimethylaminophenyl)phthalide, PA0 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (i.e., Crystal Violet Lactone), PA0 3,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide, PA0 3,3-bis(p-diethylaminophenyl)-6-chlorophthalide, PA0 3,3-bis(p-dibutylaminophenyl)phthalide, PA0 3-cyclohexylamino-6-chlorofluoran, PA0 3-dimethylamino-5,7-dimethyifluoran, PA0 3-diethylamino-7-chlorofluoran, PA0 3-diethylamino-7-methylfluoran, PA0 3-diethylamino-7,8-benzfluoran, PA0 3-diethylamino-6-methyl-7-chlorofluoran, PA0 3-(N-p-tolyl-N-ethylamino)-5-methyl-7-anilinofluoran, PA0 3-pyrrolidino-6-methyl-7-anilinofluoran, PA0 2-[N-(3'-trifluoromethylphenyl)amino]-6-diethylaminofluoran, PA0 2-[3,6-bis(diethylamino)-9-(o-chloroanilino)xanthyl]-benzoic acid lactam, PA0 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)-fluoran, PA0 3-diethylamino-7-(o-chloroanilino)fluoran, PA0 3-di-n-butylamino-7-(o-chloroanilino)fluoran, PA0 3-(N-methyl-N-n-amylamino)-6-methyl-7-anilinofluoran, PA0 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluoran, PA0 3-diethylamino-6-methyl-7-anilinofluoran, PA0 3-(N, N-diethylamino)-5-methyl-7-(N, N-dibenzylamino)-fluoran, PA0 benzoyl leuco methylene blue, PA0 6'-chloro-8'-methoxybenzoindolino spiropyran, PA0 6'-bromo-3'-methoxybenzoindolino spiropyran, PA0 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthali de, PA0 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl)phthalid e, PA0 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphen yl)phthalide, PA0 3-(N-ethyl-N-tetrahydroturfurylamino)-6-methyl-7-anilinofluoran, PA0 3-(N-ethyl-N-2-ethoxypropylamino)-6-methyl-7-anilinofluoran, PA0 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluoran, PA0 3-morphorino-7-(N-propyltrifluoromethylanilino)-fluoran, PA0 3-pyrrolidino-7-m-trifluoromethylanilinofluoran, PA0 3-diethylamino-5-chloro-7-(N-benzyltrifluoromethylanilino)fluoran, PA0 3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluoran, PA0 3-diethylamino-5-chloro-7-(.alpha.-phenylethylamino) fluoran, PA0 3-(N-ethyl-p-toluidino)-7-(.alpha.-phenylethylamino) fluoran, PA0 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran, PA0 3-diethylamino-5-methyl-7-(.alpha.-phenylethylamino) fluoran, PA0 3-diethylamino-7-piperidinofluoran, PA0 2-chloro-3-(N-methyltoluidino)-7-(p-n-butylanilino)-fluoran, PA0 3-(N-methyl-N-isopropylamino)-6-methyl-7-anilinofluoran, PA0 3-di-n-butylamino-6-methyl-7-anilinofluoran, PA0 3,6-bis(dimethylamino)fluorenespiro(9,3')-6'-dimethylaminophthalide, PA0 3-(N-benzyl-N-cyclohexylamino)-5,6-benzo-7-.alpha.-naphthylamino-4'-bromofl uoran, PA0 3-diethylamino-6-chloro-7-anilinofluoran, PA0 3-diethylamino-6-methyl-7-mesidino-4', 5'-benzofluoran, PA0 3-N-methyl-N-isopropyl-6-methyl-7-anilinofluoran, PA0 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluoran, and PA0 3-diethylamino-6-methyl-7-(2', 4'-dimethylanilino)-fluoran. PA0 4,4'-isopropylidenediphenol, PA0 4,4'-isopropylidenebis(o-methylphenol), PA0 4,4'-sec-butylidenebisphenol, PA0 4,4'-isopropylidenebis(2-tert-butylphenol), p-nitrobenzoic acid zinc salt, PA0 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimetylbenzyl)-isocyanuric acid, PA0 2,2-(3,4'-dihydroxydiphenyl)propane, PA0 bis(4-hydroxy-3-methylphenyl)sulfide, PA0 4-[.beta.-(p-methoxyphenoxy)ethoxy]salicylate, PA0 1,7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane, PA0 1,5-bis(4-hydroxyphenylthio)-5-oxapentane, PA0 monocalcium salts of monobenzylphthalate, PA0 4,4'-cyclohexylidenediphenol, PA0 4,4'-isopropylidenebis(2-chlorophenol), PA0 2,2'-methylenebis(4-methyl-6-tert-butylphenol), PA0 4,4'-butylidenebis(6-tert-butyl-2-methyl)phenol, PA0 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl) butane, PA0 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, PA0 4,4'-thiobis(6-tert-butyl-2-methyl)phenol, PA0 4,4'-diphenolsulfone, PA0 4-isoproxy-4'-hydroxydiphenylsulfone, PA0 4-benzyloxy-4'-hydroxydiphenylsulfone, PA0 4,4'-diphenolsulfoxide, PA0 isopropyl p-hydroxybenzoate, PA0 benzyl p-hydroxybenzoate, PA0 benzyl protocatechuate, PA0 stearyl gallate, PA0 lauryl gallate, PA0 octyl gallate, PA0 1,3-bis(4-hydroxyphenylthio)propane, PA0 N,N'-diphenylthiourea, PA0 N,N'-di(m-chlorophenyl)thiourea, PA0 salicylanilide, PA0 bis(4-hydroxyphenyl)methyl acetate, PA0 bis(4-hydroxyphenyl)benzyl acetate, PA0 1,3-bis(4-hydroxycumyl)benzene, PA0 1,4-bis(4-hydroxycumyl)benzene, PA0 2,4'-diphenolsulfone, PA0 2,2'-diallyl-4,4'-diphenolsulfone, PA0 3,4-dihydroxy-4'-methyldiphenylsulfone, PA0 1-acetyloxy-2-naphthoic acid zinc salt, PA0 2-acetyloxy-1-naphthoic acid zinc salt, PA0 2-acetyloxy-3-naphthoic acid zinc salt, PA0 .alpha.,.alpha.-bis(4-hydroxyphenyl)-.alpha.-methyltoluene, PA0 antipyrine complex of zinc thiocyanate, PA0 tetrabromobisphenol A, PA0 tetrabromobisphenol S, PA0 4,4'-thiobis(2-methylphenol), and PA0 4,4'-thiobis(2-chlorophenol). PA0 (1) a coloring agent and a coloring developer are dispersed or dissolved in water or an inorganic solvent together with a binder resin to prepare a coloring layer coating liquid; and PA0 (2) the coating liquid is coated by any known coating method on a substrate and then dried to form a coloring layer. PA0 (1) hollow particles are dispersed in water together with a binder resin such as a known water-soluble resin or an aqueous resin emulsion to prepare a heat insulating layer coating liquid; and PA0 (2) the coating liquid is coated on a substrate and then dried to form a heat insulating layer. PA0 (1) an expansive filler and a binder resin are mixed to prepare a heat insulating layer coating liquid; PA0 (2) the heat insulating layer coating liquid is coated on a substrate and then dried; and PA0 (3) the heat insulating layer is heated by contacting a heat plate to form an expansion type heat insulating layer in which the filler is expanded.
Images are recorded on the series of labels formed on the liner with a recording machine and each of the image recorded labels is attached on packages or goods one by one by hand or by using a labeling machine after separating the label from the liner.
The thermosensitive recording label with a liner is useful but has the following disadvantages:
Japanese Laid-Open Patent Publication No. 63-303387 and Japanese Utility Model Publication No. 5-11573 have disclosed liner-less thermosensitive recording materials which have a thermosensitive adhesive layer. However, these materials have the following disadvantages:
In addition, Japanese Laid-Open Patent Publications Nos. 63-152686, 6-57226 and 6-57233 have disclosed resins for use in a liner-less adhesive layer of non-thermosensitive recording labels. However, the adhesive layer including any one or more of these resins cannot securely adhere to the wrapping films such as polyvinyl chloride films and polyethylene films, too.
Because of these reasons, a need exists for a liner-less thermosensitive recording label which can securely adhere to various receiving materials, and more particularly to wrapping films such as polyvinyl chloride and polyethylene, and which has good resistance to blocking when the label is wound.